1. Technical Field of the Invention
The present invention relates to a device for trimming when using tree-processing machinery.
2. Description of the Background Art
When processing trees, trimming the tree trunks constitutes a large part of the tree-processing time, whereby a problem is to make the trimming process as efficient as possible, i.e. to achieve as xe2x80x9ccleanxe2x80x9d a trunk as possible. The actual tree harvesting machinery in the form of a felling head or working-up machinery for tree trunks normally includes two pairs of gripping arms, of which at least one pair acts as trimming knives where the arms grip hold of the tree trunk and hold it up against a stop on the tree harvester. To achieve as complete a trimming as possible, this stop can be designed as a third trimming knife that is fixed in position or spring-cushioned against the tree trunk. The gripping arms and the trimming knives of the tree harvester have a radius of curvature sufficient to be able to grasp the sizes that are found, i.e. tree trunks with diameters of about 60 cm. As the diameter of the trunk decreases during the course of the travel of the trunk through the machinery, the trunk will certainly be lifted up against the third knife with the help of the gripping arms but, due to their relatively large radius of curvature that is normally adapted to the thicker part of the trunk, the trimming will become less effective the more the diameter of the trunk decreases.
The aim of the invention is to achieve effective trimming even of the narrower part of the tree trunk, which is possible through the invention having the characteristics stated in the claims.